Conventionally, an operating program of an industrial robot is created by an instruction to the robot, and the robot has a teaching playback function. As one of the teaching types of industrial robots as described above, a direct teaching type is known. By the direct teaching type, a teaching person, to performs the teaching by manually moving an arm of the robot to a position he/she wants to teach, and the robot itself stores positional information (i.e., taught position) of a position sensor. Patent Documents 1 and 2 disclose technologies related to this kind of teaching of the robot.
In a direct teaching type robot according to Patent Document 1, a force sensor which detects a force applied to a wrist part is provided to this wrist part, the robot operates by a compliance control which uses the detection signal as an input, the robot is moved by a teaching person applying a force to a tool, and the teaching person positions the tool at a position where the teaching person intends by a manual operation, to input the positional information into the robot. In this robot, upon the movement of a tip end of the tool, a free motion in which the operation of the robot is not restrained and a motion in which the operation is restrained on a specific straight line or a plane can be selected.
Moreover, in a robot teaching device according to Patent Document 2, a robot is moved according to a pressing force so that the robot becomes a taught position and posture, and the position and posture of the robot after movement are taught. In this robot teaching device, when the robot is within a given effective area, the external force applied to the robot is detected or estimated, and a movement based on the detected or estimated external force is permitted. This movement is restricted to a movement in a specific direction, and/or a change in the posture about the specific direction.